Stop calling WTF::initializeMainThread() in JSGlobalContextCreate*(). I started doing so in <https://trac.webkit.org/changeset/248533> but it is causing crashes for apps using this JS API on background threads. It is also no longer necessary as of <https://trac.webkit.org/changeset/249064>.
<rdar://problem/55453612>
Created attachment 379077 [details] Patch
Comment on attachment 379077 [details] Patch r=me if bots are green.
Comment on attachment 379077 [details] Patch Clearing flags on attachment: 379077 Committed r250062: <https://trac.webkit.org/changeset/250062>
All reviewed patches have been landed. Closing bug.
FYI, I am looking into writing an API test for this, to avoid this happening again in the future.